Burn Wound Microbiome Differences in the Setting of Xenografted vs. Autografted Wounds

Author(s):
Mary Oliver; John Keyloun; Jeremy Chen See; Robert Ball; Bonnie Carney; Lauren Nosanov; Melissa McLawhorn; justin wright; Regina Lamendella; Lauren Moffatt; Jeffrey Shupp

Background:

As infection remains the leading cause of morbidity and mortality in burn patients, current burn care practice is focused on rapid wound closure and healing to mitigate this adverse effect. Autografting is standard burn wound care, and additionally, xenografts, human skin allografts, and biosynthetic dressings are other methods which provide promising skin substitute. Differences in xenograft versus autograft procedures (minimal excision vs. full excision) can contribute to variances in the microflora of the wound bed which may have local and systemic effects on healing.

Hypothesis:

Microbiome characteristics of xenografted wounds will be more integrous with host microflora due to minimal excision of the wound bed.

Methods:

31 eligible patients were enrolled with thermal burns of TBSA ≤10%. Wounds were either autografted with meshed split thickness skin grafts or xenografted with porcine xenograft. Patients were assessed at 4 timepoints: pre-excision, post excision, dressing takedown, and follow up visit. Wound bed swabs, buccal swabs, blood, biopsies and images were taken at each time point. %reepithelization measurements were calculated, and swabs were used for 16srRNA sequencing.

Results:

Overall %reepithelization was higher in autografted wounds at follow up (92.3% vs. 76.9%, p=0.03). Considering Faith’s phylogenic diversity metric, xenografted buccal swabs and wound bed swabs showed higher diversity than autografted swabs (p=0.048 and p=0.0002, respectively). In the wound bed swabs, the dressing take down and follow up time points were drivers of overall xenograft diversity (p=0.035 and p=0.012, respectively). Moreover, linear discriminant analysis effect size (LEfSe) plot showed significant enrichment of 7 taxa in buccal swabs from xenografted wounds as compared to 4 in the autografted. Of note, Streptococcus, and Granulicatella were among enriched xenograft taxa. In the wound bed both xenograft and autograft presented 4 enriched taxa; including Staphylococcus and Burkholderia in xenograft and Enterobacter and Serratia in autograft.

Conclusions:

Xenograft swabs exhibited taxa that are resident microbes of the microbiome whereas autografted taxa trended to be representative of pathogenic microbes. The integrity of xenograft diversity remains consistent throughout healing to the follow up timepoint. Further analyses into microflora shifts in oral and wound microbiome in autografted wounds versus other grafting solutions will help inform clinicians of proper interventions in the care of burn patients.